May 12, 2009

interest region (point) detector and descriptors

K. Mikolajczyk, T. Tuytelaars, C. Schmid, A. Zisserman, J. Matas, F. Schaffalitzky, T. Kadir and L. Van Gool, A comparison of affine region detectors. In IJCV 65(1/2):43-72, 2005. PDF
K. Mikolajczyk, C. Schmid, A performance evaluation of local descriptors. In PAMI 27(10):1615-1630 . PDF

Affine Covariant Regions @ vgg
Feature Detectors and Descriptors: The State Of The Art and Beyond

vgg 目前提供
以下 detector
Scale & affine invariant feature: harris affine, hessian affine 等(另有一新版本,可以设置更多参数和控制阈值输出更多特征)
scale saliency
SURF
fast

另有
INRIA 提供的 scale/affine invariant detector
其中 hog, log 是 vgg 没有提供的,可以使用

这些有些有 win32 版本,要详查


Descriptor:
VGG 提供的可以计算steerable filters, SIFT descriptor, moments, differential invariants, complex filters, shape context, spin images, PCA-SIFT


INRIA 也提供一个

feature space 将 detector 和 descriptor 结合在一起(descriptor 只有 sift 和 gloh)
如上的格式是统一的

--------------------
 file format 1:
n_descriptor_dimension
m_nb_of_descriptors_in file
 u v a b c desc_1 desc_2 ......desc_n
:

--------------------

where a(x-u)(x-u)+2b(x-u)(y-v)+c(y-v)(y-v)=1

 file format 2:
vector_dimension
nb_of_descriptors
x y cornerness scale/patch_size angle object_index  point_type laplacian_value extremum_type mi11 mi12 mi21 mi22 desc_1 ...... desc_vector_dimension

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